1. Field of the Invention
This invention relates generally to infrared communications systems and, more specifically, to a System and Method for Providing an Improved Standby Mode for Infrared Data Transceivers.
2. Description of Related Art
As technology becomes continually more accessible to the “common man,” the ability to use, store, transfer and otherwise manipulate information has become the focus of most businesses as well as for the individual consumer. Access to the information resources is commonly by some sort of network system, including World Wide Web, “Intranets”, local area networks, wide area networks, as well as corporate databases.
While the conventional method for connecting to one of these information networks has been via cable and wire, as the reliance upon connectivity to information has deepened, the desire to gain such access from mobile or portable devices has strengthened. These portable devices, such as Personal Digital Assistants, hand-held computers, cellular telephones, and even digital cameras are now being connected to each other and to networks via Infrared Data Communications. In fact, it is virtually impossible to purchase a notebook computer today that does not include an Infrared Data Communications assembly resident within it.
One drawback of these portable devices or appliances is their inherent dependency upon portable power sources (i.e. batteries of some sort). As functionality is added to the device, so is demand upon the portable power source, therefore any way of reducing the demand upon the portable power source is extremely desirable. One particular system that can place a significant demand upon the portable power source is the Ir transceiver system—FIG. 1 provides pertinent details about how these systems function. FIG. 1 is an illustration of a pair of prior Ir-enabled appliances 10 and 12 in standby mode. Standby mode is that condition to which the appliance returns when the appliance is not actively engaged in Ir communications. Each appliance, comprises (in pertinent part) an Ir transceiver system 14 and 16 that is powered by power supply means 18 and 20 for powering the electronics and mechanical devices contained within the appliances 10 and 12. While the power supply means 18 and 20 may be external electrical power, the means 18 and 20 that is pertinent to this discussion is a portable battery-type power supply means because its available charge is limited. The limited life span of the battery-type power supply means 18 and 20 is the focus of the present invention.
In the prior appliances 10 and 12, the Ir transceiver systems 14 and 16 operate in a constant, full-power demand condition, as demonstrated by the IrXS (Infrared transmission system) Power State indicators 22 and 24 (these are simply representations to indicate a power load condition—they are not intended to represent actual devices). The problem with the prior appliances 10 and 12 resides with the “standby” or “sleep” mode of the If transceiver systems 14 and 16. When in standby mode, as represented by balloons 26 and 28, there are no emissions from the systems 14 and 16; the systems 14 and 16 are simply monitoring their environment for a “discovery” signal. Discovery signals are Ir signals in a particular frequency band, currently established by the IRDA (Infrared Data Association) at 9600 baud, that one appliance 10 or 12 sends to another appliance to “wake up” the other appliance in preparation for the commencement of Ir communications. As illustrated by FIG. 1, the prior appliances 10 and 12 are in full-power demand conditions 22 and 24, even though they are sleeping. Even though the transceiver systems 14 and 16 are performing no work beyond simply listening, they are imposing the same drain on the power supply means 18 and 20 that a fully active transceiver 14 and 16 would draw. As discussed earlier, any reduction in power demand will provide significant benefits to the user of these portable Ir-enabled appliances. What is needed, therefore, is a means for reducing the power drain on the power supply means 18, for example, when portable Ir-enabled appliances are in standby mode.